PROGNOSTIC RELEVANCE OF CARCINOEMBRYONIC ANTIGEN AND ESTROGEN-RECEPTOR STATUS IN BREAST-CANCER PATIENTS

Background. Expression of carcinoembryonic antigen (CEA) has been repo rted in 10-95% of breast cancer. Its value as a predictor of disease p rogression is controversial. Methods. The expression of CEA in 202 Sta ges I and II breast carcinomas was assessed by immunohistochemistry, a nd the results were correlated with various histologic and clinical pa rameters to establish CEA's biologic relevance. The mean follow-up of the patients was 6.5 years. The monoclonal antibody used does not cros s-react with other molecules in the CEA gene family. Results. One hund red, thirteen (56%) tumors expressed CEA in more than 15% of the cells . Expression of CEA was associated with positive estrogen receptor (ER ) status (P = 0.003). Univariate Cox regression analysis showed that, whereas disease free survival (DFS) and overall survival (OS) were not associated significantly with CEA expression, tumor size, nuclear gra de, ER status, lymph node metastases, and stage were. When ER status w as stratified to CEA expression, patients who were ER negative and had CEA-negative tumors had a 3.9 times higher risk (P = 0.032) of death than did the patients with CEA-positive tumors.Cox regression analysis revealed that ER was the only parameter with significant interacting effect with CEA. Multivariate, stepwise Cox regression analysis showed that CEA expression, tumor size, and nuclear grade were the only sign ificant independent predictors of DFS, and nuclear grade and lymph nod e metastasis the only significant predicotrs of OS in the ER-positive group. The only significant independent predictor of DFS and OS in the ER-negative group was CEA. When CEA expression was stratified to ER s tatus, patients whose tumors lacked CEA and ER had threefold higher ri sk of disease relapse (P = 0.002) and a 5.3-fold higher risk of death (P = 0.0001) than those with ER-positive and CEA-negative tumors. Mult ivariate analysis showed that the association between CEA and ER was e nhanced further after compensating for other parameters with independe nt predictive value. Conclusions. The association between CEA and ER w as the most important independent predictor of a subgroup of patients (CEA-negative, ER-positive) with the most favorable prognosis. The res ults imply that the association of several tumor markers may provide t umor profiles with superior predictive value than a single parameter.